One method at present in use for the mounting of a lock assembly in an aperture in a panel in a motor vehicle includes providing a flange on the lock housing, fitting the housing in the aperture from one side of the panel so that the flange bears against the surround of the aperture, and engaging a spring clip or other fastener with the body of the housing so as to bear against the other side of the panel. Since this method involves operations effected from both sides of the panel, i.e. fitting of the assembly from one side and engagement of the spring clip from the other side, it cannot be effected as efficiently as would be the case if the whole assembly operation could be effected from one side of the panel. It is thus an object of the invention to provide an improved form of lock assembly the design of which is such as to enable the necessary operations for insertion of the assembly in an aperture in a panel to be carried out from one side only of the panel.